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Efficacy of Intra‐Articular Botulinum Toxin Type A in Painful Knee Osteoarthritis: A Pilot Study
Author(s) -
Boon Andrea J.,
Smith Jay,
Dahm Diane L.,
Sorenson Eric J.,
Larson Dirk R.,
FitzGibbon Patrick D.,
Dykstra Dennis D.,
Singh Jasvinder A.
Publication year - 2010
Publication title -
pmandr
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.617
H-Index - 66
eISSN - 1934-1563
pISSN - 1934-1482
DOI - 10.1016/j.pmrj.2010.02.011
Subject(s) - medicine , visual analogue scale , osteoarthritis , randomized controlled trial , adverse effect , arthritis , patient satisfaction , physical therapy , outpatient clinic , surgery , anesthesia , alternative medicine , pathology
Objective To evaluate the efficacy and safety of botulinum toxin type A (BoNT‐A) injected intra‐articularly in 60 subjects with moderate pain and functional impairment secondary to knee osteoarthritis. The study investigators hypothesized that intra‐articular BoNT‐A would result in statistically significant improvements in pain and function at 8 weeks. Design Double‐blind, randomized, single tertiary care academic medical center trial with 6‐month follow‐up. Patients Sixty patients aged 40 years or older with painful osteoarthritis of the knee who had failed physical therapy, medications, and/or injection therapy presenting to the musculoskeletal or orthopedic outpatient clinics at a large tertiary care medical institution. All 60 patients completed 8‐week follow‐up, but only 32 patients completed the 26‐week follow‐up. Methods Subjects were randomized to receive a single injection of corticosteroid, low‐dose BoNT‐A (100 units), or high‐dose BoNT‐A (200 units). Outcome measures were compared at baseline, 4, 8, 12, and 26 weeks after injection. Main Outcome Measurements The primary outcome measure was pain visual analog scale (VAS) at 8 weeks. Secondary outcome measures included Western Ontario McMaster Arthritis Index, Short Form‐36 scores, patient global assessment, 40‐meter timed walk, and adverse effects. Results The primary end point was pain VAS score at 8 weeks, which decreased within each group but only reached statistical significance in the low‐dose BoNT‐A group. In the intra‐articular corticosteroid group, VAS decreased from 6.4 ± 1.8 to 5.4 ± 2.3 ( P = .15); for low‐dose BoNT‐A, from 6.6. ± 1.9 to 4.5 ± 2.2 ( P = .01); and for high‐dose BoNT‐A, from 6.6 ± 1.4 to 5.9 ± 2.4 ( P = .15). All groups showed statistically significant improvements in Western Ontario McMaster Arthritis Index scores (pain, stiffness, function) at 8 weeks. No serious adverse events were noted in any group. Conclusions This pilot study supports a possible role for BoNT‐A as a treatment option for symptomatic knee osteoarthritis; however, larger double‐blind randomized studies are needed to determine whether BoNT‐A is more effective than placebo in this patient population.